Primary intermediates for oxidative coloration of hair

ABSTRACT

Primary intermediates for hair coloring compositions for oxidative dyeing of hair are compounds of the formula (1): 
                 
 
where R 1  and R 2  are each individually selected from a hydrogen atom, a C 1  to C 3  alkyl group, a C 1  to C 5  mono or dihydroxyalkyl group, phenyl or benzyl optionally substituted with an alkoxy group, or R 1  and R 2  together with the nitrogen atom to which they are attached form a piperazine, piperidine, imidazole, or morpholine ring.

This is a divisional of U.S. application Ser. No. 10/052,967, filed Jan.18, 2002, now U.S. Pat. No. 6,750,355, which claims the priority of U.S.Provisional Application 60/263,588, filed Jan. 23, 2001.

FIELD OF THE INVENTION

This invention relates to new compounds and compositions containingthese compounds as primary intermediates for oxidative coloring of hairfibers.

BACKGROUND TO THE INVENTION

Coloration of hair is a procedure practiced from antiquity employing avariety of means. In modern times, the method most extensively to colorhair is an oxidative dyeing process utilizing one or more oxidative haircoloring agents in combination with one or more oxidizing agents.

Most commonly a peroxy oxidizing agent is used in combination with oneor more oxidative hair coloring agents, generally small moleculescapable of diffusing into hair and comprising one or more primaryintermediates and one or more couplers. In this procedure, a peroxidematerial, such as hydrogen peroxide, is employed to activate the smallmolecules of primary intermediates so that they react with couplers toform larger sized compounds in the hair shaft to color the hair in avariety of shades and colors.

A wide variety of primary intermediates and couplers have been employedin such oxidative hair coloring systems and compositions. Among theprimary intermediates employed there may be mentionedp-phenylenediamine, p-toluenediamine, p-aminophenol,4-amino-3-methylphenol, N,N-bis(2-hydroxyethyl)-p-phenylene diamine,1-(2-hydroxyethyl)-4,5-diaminopyrazole and as couplers there may bementioned resorcinol, 2-methylresorcinol, 3-aminophenol,2,4-diaminophenoxyethanol, and 5-amino-2-methylphenol.

There are numerous additional requirements for oxidation dye compoundsthat are used to dye human hair besides the color or the desiredintensity. Thus, the dye compounds must be unobjectionable in regard totoxicological and dermatological properties and must provide the desiredhair color with a good light fastness, good selectivity, fastness to apermanent wave treatment, acid fastness, and fastness to rubbing. Thecolor of the hair dyed with the dye compounds in each case must bestable for at least 4 to 6 weeks to light, rubbing and chemical agents.Furthermore, an additional requirement is the production of a broadpalette of different color shades using different developer and couplersubstances. For providing a yellow or orange yellow coloration to hair,resorcinol and 2-methyl resorcinol have been extensively used incombination with p-aminophenol. Coupling of p-aminophenol with 2-methylresorcinol provides weak orange yellow, while coupling of p-aminophenolwith resorcinol gives weak yellow green. 6-Amino-m-cresol (U.S. Pat. No.4,396,392) as well as direct dye 2-amino-4-nitro-6-chlorophenol is alsoused in current practices. A combination of tetraaminopyrimidine and3,4-dimethyl-2,6-dihydroxy pyridine (EP 63736 A2) or a combination of6-hydroxyindole and p-aminophenol (U.S. Pat. No. 5,279,620) are alsoused. 6-Hydroxyindole couples with p-aminophenol and p-phenylenediamineto provide golden beige and medium golden brown, respectively. However,these yellow couplers suffer from weak and dull coloration, especiallyin the presence of primary intermediates and couplers. Therefore, thereis a need to provide compounds to impart yellow and orange yellowcoloration in oxidative hair coloring without these drawbacks.

SUMMARY OF THE INVENTION

It is therefore an object of this invention to provide new primaryintermediate compounds useful for providing yellow or orange yellowcolor shades with various combinations of primary intermediates andcouplers.

It has been discovered that new compounds that are derivatives of2-aminophenol are suitable primary intermediates for hair coloringcompositions and systems for providing good oxidative coloration of hairand for providing acceptable light fastness, good selectivity, fastnessto shampooing, fastness to perspiration and permanent wave treatment,and suitable for providing a wide variety of different color shades withvarious primary intermediate and coupler compounds.

The invention provides new compounds of formula (1):

wherein R₁ and R₂ are each individually selected from hydrogen atoms, C₁to C₅ alkyl, C₁ to C₅ mono or dihydroxyalkyl, phenyl or benzyloptionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group,or R₁ and R₂ together with the nitrogen atom to which they are attachedform a C₃ to C₆, preferably C₄ to C₆, saturated or unsaturated ringoptionally containing in the ring one or more additional hetero atomsselected from O, S and N atoms.

These novel primary intermediates are used to provide coloration to hairin which there is good dye uptake by the hair and provides shades orcolors which are stable over a relatively long period of time. The novelprimary intermediates provide for dyeing of hair to impart color orshades that possess good wash fastness and do not undergo significantchanges on exposure to light or shampooing.

DETAILED DESCRIPTION OF THE INVENTION

The compounds of this invention are those of formula (1)

wherein R₁ and R₂ are each individually selected from hydrogen atoms, C₁to C₅ alkyl, C₁ to C₅ mono or dihydroxyalkyl, phenyl or benzyloptionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group,or R₁ and R₂ together with the nitrogen atom to which they are attachedform a C₃ to C₆ saturated or unsaturated ring optionally containing inthe ring one or more additional hetero atoms selected from O, S and Natoms.

Preferably R₁ and R₂ are each individually selected from a hydrogenatom, a C₁ to C₃ alkyl group, more preferably methyl groups; phenyl orbenzyl optionally substituted with an alkoxy group, more preferably amethoxy group, or R₁ and R₂ together with the nitrogen atom to whichthey are bound form a piperazine, piperidine, imidazole, or morpholinering.

Especially preferred compounds of formula (1) of this invention are thefollowing compounds:

2-amino-5-phenylaminomethyl-phenol;

2-amino-5-piperidin-1-ylmethyl-phenol; and

2-amino-5-pyridin-3-ylaminomethyl-phenol.

The new 2-aminophenol derivative compounds of formula (1) of thisinvention can be prepared according to the following reaction sequencewherein R₁ and R₂ are as defined herein before.

In this synthesis procedure the aldehyde compound of formula (2) issubjected to reductive amination with the reagent R₁R₂NH using reducingagents such as sodium triacetoxyborohydride, sodium cyanoborohydride, orpolymethylhydrosiloxane (PMHS) to produce a compound of formula (3).Catalytic hydrogenation of the compound of formula (3) with Pd/C underhydrogen produces a compound of formula (1).

SYNTHESIS EXAMPLES 1 TO 9

Employing the appropriate R₁R₂NH reagent, reducing agent and aldehyde offormula (2) in the synthesis procedure described, the following2-aminophenol derivative compounds of formula (1) of this invention canbe prepared:

2-amino-5-phenylaminomethyl-phenol;

2-amino-5-piperidin-1-ylmethyl-phenol;

2-amino-5-pyridin-3-ylaminomethyl-phenol;

2-amino-5-imidazolin-1-ylmethyl-phenol;

2-amino-5-methylaminomethyl-phenol;

2-amino-5-dimethylaminomethyl-phenol;

2-amino-5-hydroxymethylaminomethyl-phenol;

2-amino-5-morpholino-1-ylmethyl-phenol; and

2-amino-5-dipropylaminomethyl-phenol.

As used herein, the term “hair dyeing composition” (also synonymouslyreferred to herein as the hair dye composition, the hair coloringcomposition, or the hair dye lotion) refers to the compositioncontaining oxidation dyes, including the novel compounds describedherein, prior to admixture with the developer composition. The term“developer composition” (also referred to as the oxidizing agentcomposition or the peroxide composition) refers to compositionscontaining an oxidizing agent prior to admixture with the hair dyeingcomposition. The term “hair dye product” or “hair dye system” (alsoreferred to as the hair dyeing system, hair dyeing product, or haircoloring system) interchangeably refer to the combination of the hairdyeing composition and the developer composition before admixture, andmay further include a conditioner product and instructions, such productor system often being provided packaged as a kit. The term “hair dyeingproduct composition” refers to the composition formed by mixing the hairdyeing composition and the developer composition. “Carrier” (or vehicleor base) refers to the combination of ingredients contained in acomposition excluding the active agents (e.g., the oxidation hair dyesof the hair dyeing composition).

Hair coloring (i.e., hair dyeing) compositions of this invention cancontain, in combination with oxidation dye couplers, a novel primaryintermediate of this invention as the sole primary intermediate or canalso contain other primary intermediates. Thus, one or more suitableprimary intermediates may be used in combination with the novel primaryintermediates of this invention.

Suitable known primary intermediates include, for example,

p-phenylenediamine derivatives such as: benzene-1,4-diamine (commonlyknown as p-phenylenediamine), 2-methyl-benzene-1,4-diamine,2-chloro-benzene-1,4-diamine, N-phenyl-benzene-1,4-diamine,N-(2-ethoxyethyl)benzene-1,4-diamine,2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, (commonly known asN,N-bis(2-hydroxyethyl)-p-phenylenediamine)(2,5-diamino-phenyl)-methanol, 1-(2,5-diamino-phenyl)-ethanol,2-(2,5-diamino-phenyl)-ethanol, N-(4-aminophenyl)benzene-1,4-diamine,2,6-dimethyl-benzene-1,4-diamine, 2-isopropyl-benzene-1,4-diamine,1-[(4-aminophenyl)amino]-propan-2-ol, 2-propyl-benzene-1,4-diamine,1,3-bis[(4-aminophenyl)(2-hydroxyethyl)amino]propan-2-ol,N⁴,N⁴,2-trimethylbenzene-1,4-diamine, 2-methoxy-benzene-1,4-diamine,1-(2,5-diaminophenyl)ethane-1,2-diol, 2,3-dimethyl-benzene-1,4-diamine,N-(4-amino-3-hydroxy-phenyl)-acetamide, 2,6-diethylbenzene-1,4-diamine,2,5-dimethylbenzene-1,4-diamine, 2-thien-2-ylbenzene-1,4-diamine,2-thien-3-ylbenzene-1,4-diamine, 2-pyridin-3-ylbenzene-1,4-diamine,1,1′-biphenyl-2,5-diamine, 2-(methoxymethyl)benzene-1,4-diamine,2-(aminomethyl)benzene-1,4-diamine, 2-(2,5-diaminophenoxy)ethanol,N-[2-(2,5-diaminophenoxy)ethyl]-acetamide,N,N-dimethylbenzene-1,4-diamine, N,N-diethylbenzene-1,4-diamine,N,N-dipropylbenzene-1,4-diamine, 2-[(4-aminophenyl)(ethyl)amino]ethanol,2-[(4-amino-3-methyl-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol,N-(2-methoxyethyl)-benzene-1,4-diamine,3-[(4-aminophenyl)amino]propan-1-ol,3-[(4-aminophenyl)amino]propane-1,2-diol,N-{4-[(4-aminophenyl)amino]butyl}benzene-1,4-diamine, and2-[2-(2-{2-[(2,5-diaminophenyl)-oxy]ethoxy}ethoxy)ethoxy]benzene-1,4-diamine;

p-aminophenol derivatives such as: 4-amino-phenol (commonly known asp-aminophenol), 4-methylamino-phenol, 4-amino-3-methyl-phenol,4-amino-2-hydroxymethyl-phenol, 4-amino-2-methyl-phenol,4-amino-2-[(2-hydroxy-ethylamino)-methyl]-phenol,4-amino-2-methoxymethyl-phenol, 5-amino-2-hydroxy-benzoic acid,1-(5-amino-2-hydroxy-phenyl)ethane-1,2-diol,4-amino-2-(2-hydroxy-ethyl)-phenol, 4-amino-3-(hydroxymethyl)phenol,4-amino-3-fluoro-phenol, 4-amino-2-(aminomethyl)-phenol, and4-amino-2-fluoro-phenol;

o-aminophenol derivatives such as: 2-amino-phenol (commonly known aso-aminophenol), 2,4-diaminophenol, 2-amino-5-methyl-phenol,2-amino-6-methyl-phenol, N-(4-amino-3-hydroxy-phenyl)-acetamide, and2-amino-4-methyl-phenol; and

heterocyclic derivatives such as: pyrimidine-2,4,5,6-tetramine (commonlyknown as 2,4,5,6-tetraaminopyridine), 1-methyl-1H-pyrazole-4,5-diamine,2-(4,5-diamino-1H-pyrazol-1-yl)ethanol, N²,N²-dimethyl-pyridine-2,5-diamine,2-[(3-amino-6-methoxypyridin-2-yl)amino]ethanol,6-methoxy-N²-methyl-pyridine-2,3-diamine,2,5,6-triaminopyrimidin-4(1H)-one, pyridine-2,5-diamine,1-isopropyl-1H-pyrazole-4,5-diamine,1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine,1-(benzyl)-1H-pyrazole-4,5-diamine, and1-(4-chlorobenzyl)-1H-pyrazole-4,5-diamine.

The novel primary intermediates of formula (1) of this invention may beused with any suitable coupler(s) in hair coloring compositions orsystems of this invention.

Suitable known couplers include, for example:

phenols, resorcinol and naphthol derivatives such as:naphthalene-1,7-diol, benzene-1,3-diol, 4-chlorobenzene-1,3-diol,naphthalen-1-ol, 2-methyl-naphthalen-1-ol, naphthalene-1,5-diol,naphthalene-2,7-diol, benzene-1,4-diol, 2-methyl-benzene-1,3-diol,7-amino-4-hydroxy-naphthalene-2-sulfonic acid,2-isopropyl-5-methylphenol, 1,2,3,4-tetrahydro-naphthalene-1,5-diol,2-chloro-benzene-1,3-diol, 4-hydroxy-naphthalene-1-sulfonic acid,benzene-1,2,3-triol, naphthalene-2,3-diol,5-dichloro-2-methylbenzene-1,3-diol, 4,6-dichlorobenzene-1,3-diol, and2,3-dihydroxy-[1,4]naphthoquinone;

m-phenylenediamines such as: 2,4-diaminophenol, benzene-1,3-diamine,2-(2,4-diamino-phenoxy)-ethanol,2-[(3-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol,2-mehyl-benzene-1,3-diamine,2-[[2-(2,4-diamino-phenoxy)-ethyl]-(2-hydroxy-ethyl)-amino]-ethanol,4-{3-[(2,4-diaminophenyl)oxy]propoxy}benzene-1,3-diamine,2-(2,4-diamino-phenyl)-ethanol,2-(3-amino-4-methoxy-phenylamino)-ethanol,4-(2-amino-ethoxy)-benzene-1,3-diamine, (2,4-diamino-phenoxy)-aceticacid, 2-[2,4-diamino-5-(2-hydroxy-ethoxy)-phenoxy]-ethanol,4-ethoxy-6-methyl-benzene-1,3-diamine,2-(2,4-diamino-5-methyl-phenoxy)-ethanol,4,6-dimethoxy-benzene-1,3-diamine,2-[3-(2-hydroxy-ethylamino)-2-methyl-phenylamino]-ethanol,3-(2,4-diamino-phenoxy)-propan-1-ol, N-[3-(dimethylamino)phenyl]urea,4-methoxy-6-methylbenzene-1,3-diamine,4-fluoro-6-methylbenzene-1,3-diamine,2-({3-[(2-hydroxyethyl)amino]-4,6-dimethoxyphenyl}-amino)ethanol,3-(2,4-diaminophenoxy)-propane-1,2-diol,2-[2-amino-4-(methylamino)-phenoxy]ethanol,2-[(5-amino-2-ethoxy-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol,2-[(3-aminophenyl)amino]ethanol, N-(2-aminoethyl)benzene-1,3-diamine,4-{[(2,4-diamino-phenyl)oxy]methoxy}-benzene-1,3-diamine, and2,4-dimethoxybenzene-1,3-diamine;

m-aminophenols such as: 3-amino-phenol,2-(3-hydroxy-4-methyl-phenylamino)-acetamide,2-(3-hydroxy-phenylamino)-acetamide, 5-amino-2-methyl-phenol,5-(2-hydroxy-ethylamino)-2-methyl-phenol, 5-amino-2,4-dichloro-phenol,3-amino-2-methyl-phenol, 3-amino-2-chloro-6-methyl-phenol,5-amino-2-(2-hydroxy-ethoxy)-phenol,2-chloro-5-(2,2,2-trifluoro-ethylamino)-phenol,5-amino-4-chloro-2-methyl-phenol, 3-cycloperitylamino-phenol,5-[(2-hydroxyethyl)amino]-4-methoxy-2-methylphenol,5-amino-4-methoxy-2-methylphenol, 3-(dimethylamino)phenol,3-(diethylamino)phenol, 5-amino-4-fluoro-2-methylphenol,5-amino-4-ethoxy-2-methylphenol, 3-amino-2,4-dichloro-phenol,3-[(2-methoxyethyl)amino]phenol, 3-[(2-hydroxyethyl)amino]phenol,5-amino-2-ethyl-phenol, 5-amino-2-methoxyphenol,5-[(3-hydroxypropyl)amino]-2-methylphenol,3-[(3-hydroxy-2-methylphenyl)-amino]propane-1,2-diol, and3-[(2-hydroxyethyl)amino]-2-methylphenol; and

heterocyclic derivatives such as: 3,4-dihydro-2H-1,4-benzoxazin-6-ol,4-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one,6-methoxyquinolin-8-amine, 4-methylpyridine-2,6-diol,2,3-dihydro-1,4-benzodioxin-5-ol, 1,3-benzodioxol-5-ol,2-(1,3-benzodioxol-5-ylamino)ethanol, 3,4-dimethylpyridine-2,6-diol,5-chloropyridine-2,3-diol, 2,6-dimethoxypyridine-3,5-diamine,1,3-benzodioxol-5-amine,2-{[3,5-diamino-6-(2-hydroxy-ethoxy)-pyridin-2-yl]oxy}-ethanol,1H-indol-4-ol, 5-amino-2,6-dimethoxypyridin-3-ol, 1H-indole-5,6-diol,1H-indol-7-ol, 1H-indol-5-ol, 1H-indol-6-ol,6-bromo-1,3-benzodioxol-5-ol, 2-aminopyridin-3-ol, pyridine-2,6-diamine,3-[(3,5-diaminopyridin-2-yl)oxy]propane-1,2-diol,5-[(3,5-diaminopyridin-2-yl )oxy]pentane-1,3-diol, 1H-indole-2,3-dione,indoline-5,6-diol, 3,5-dimethoxypyridine-2,6-diamine,6-methoxypyridine-2,3-diamine, and3,4-dihydro-2H-1,4-benzoxazin-6-amine.

Preferred primary intermediates include:

p-phenylenediamine derivatives such as: 2-methyl-benzene-1,4-diamine,benzene-1,4-diamine, 1-(2,5-diamino-phenyl)-ethanol,2-(2,5-diamino-phenyl)-ethanol, N-(2-methoxyethyl)benzene-1,4-diamine,2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, and1-(2,5-diaminophenyl)ethane-1,2-diol;

p-aminophenol derivatives such as 4-amino-phenol, 4-methylamino-phenol,4-amino-3-methyl-phenol, 4-amino-2-methoxymethyl-phenol, and1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol;

o-aminophenol derivatives such as: 2-amino-phenol,2-amino-5-methyl-phenol, 2-amino-6-methyl-phenol,N-(4-amino-3-hydroxy-phenyl)-acetamide, and 2-amino-4-methyl-phenol; and

heterocyclic derivatives such as: pyrimidine-2,4,5,6-tetramine,1-methyl-1H-pyrazole-4,5-diamine,2-(4,5-diamino-1H-pyrazol-1-yl)ethanol,1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine,1-(benzyl)-1H-pyrazole-4,5-diamine, andN²,N²-dimethyl-pyridine-2,5-diamine.

Preferred couplers include:

phenols, resorcinol and naphthol derivatives such as:naphthalene-1,7-diol, benzene-1,3-diol, 4-chlorobenzene-1,3-diol,naphthalen-1-ol, 2-methyl-naphthalen-1-ol, naphthalene-1,5-diol,naphthalene-2,7-diol, benzene-1,4-diol, 2-methyl-benzene-1,3-diol, and2-isopropyl-5-methylphenol;

m-phenylenediamines such as: benzene-1,3-diamine,2-(2,4-diamino-phenoxy)-ethanol,4-{3-[(2,4-diaminophenyl)oxy]propoxy}benzene-1,3-diamine,2-(3-amino-4-methoxy-phenylamino)-ethanol,2-[2,4-diamino-5-(2-hydroxy-ethoxy)-phenoxy]-ethanol, and3-(2,4-diamino-phenoxy)-propan-1-ol;

m-aminophenols such as: 3-amino-phenol, 5-amino-2-methyl-phenol,5-(2-hydroxy-ethylamino)-2-methyl-phenol, and 3-amino-2-methyl-phenol;and

heterocyclic derivatives such as: 3,4-dihydro-2H-1,4-benzoxazin-6-ol,4-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, 1,3-benzodioxol-5-ol,1,3-benzodioxol-5-amine, 1H-indol-4-ol, 1H-indole-5,6-diol,1H-indol-7-ol, 1H-indol-5-ol, 1H-indol-6-ol, 1H-indole-2,3-dione,pyridine-2,6-diamine, and 2-aminopyridin-3-ol.

Most preferred primary intermediates include:

p-phenylenediamine derivatives such as: 2-methyl-benzene-1,4-diamine,benzene-1,4-diamine, 2-(2,5-diamino-phenyl)-ethanol,1-(2,5-diamino-phenyl)-ethanol, and2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol;

p-aminophenol derivatives such as: 4-amino-phenol, 4-methylamino-phenol,4-amino-3-methyl-phenol, and1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol;

o-aminophenols such as: 2-amino-phenol, 2-amino-5-methyl-phenol,2-amino-6-methyl-phenol, and N-(4-amino-3-hydroxy-phenyl)-acetamide; and

heterocyclic derivatives such as: pyrimidine-2,4,5,6-tetramine,2-(4,5-diamino-1H-pyrazol-1-yl)ethanol,1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine, and1-(benzyl)-1H-pyrazole-4,5-diamine.

Most preferred couplers include:

phenols, resorcinol and naphthol derivatives such as: benzene-1,3-diol,4-chlorobenzene-1,3-diol, naphthalen-1-ol, 2-methyl-naphthalen-1-ol, and2-methyl-benzene-1,3-diol;

m-phenylenediamine such as: 2-(2,4-diamino-phenoxy)-ethanol,2-(3-amino-4-methoxy-phenylamino)-ethanol,2-[2,4-diamino-5-(2-hydroxy-ethoxy)-phenoxy]-ethanol, and3-(2,4-diamino-phenoxy)-propan-1-ol;

m-aminophenols such as: 3-amino-phenol, 5-amino-2-methyl-phenol,5-(2-hydroxy-ethylamino)-2-methyl-phenol, and 3-amino-2-methyl-phenol;and

heterocyclic derivatives such as: 3,4-dihydro-2H-1,4-benzoxazin-6-ol,4-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, 1H-indol-6-ol, and2-aminopyridin-3-ol.

Understandably, the coupler compounds and the primary intermediatecompounds, including the novel compounds of the invention, in so far asthey are bases, can be used as free bases or in the form of theirphysiologically compatible salts with organic or inorganic acids, suchas hydrochloric, citric, acetic, tartaric, or sulfuric acids, or, in sofar as they have aromatic OH groups, in the form of their salts withbases, such as alkali phenolates.

The total amount of dye precursors (e.g., primary intermediate andcoupler compounds, including the novel compounds of this invention) inthe hair dyeing compositions of this invention is generally from about0.002 to about 20, preferably from about 0.04 to about 10, and mostpreferably from about 0.1 to about 7.0 weight percent, based on thetotal weight of the hair dyeing composition. The primary intermediateand coupler compounds are generally used in molar equivalent amounts.However, it is possible to use the primary intermediate compounds ineither excess or deficiency, i.e., a molar ratio of primary intermediateto coupler generally ranging from about 5:1 to about 1:5.

The hair dyeing compositions of this invention will contain the primaryintermediate of this invention in an effective dyeing amount, generallyin an amount of from about 0.001 to about 10 weight percent by weight ofthe hair dye composition, preferably from about 0.01 to about 5.0 weightpercent. Other primary intermediates, when present, are typicallypresent in an amount such that in aggregate the concentration of primaryintermediates in the composition is from about 0.002 to about 10 weightpercent, preferably from about 0.01 to about 5.0 weight percent. Thecoupler(s) are present in an effective dyeing concentration, generallyan amount of from about 0.001 to about 10.0 weight percent by weight ofthe hair dye composition, preferably from about 0.01 to about 5.0 weightpercent. The remainder of the hair dye composition comprises a carrieror vehicle for the couplers and primary intermediates, and comprisesvarious adjuvants as described below.

Any suitable carrier or vehicle, generally an aqueous or hydroalcoholicsolution, can be employed, preferably an aqueous solution. The carrieror vehicle will generally comprise more than 80 weight percent of thehair dye composition, typically 90 to 99 weight percent, preferably 94to 99 weight percent. The hair coloring compositions of this inventionmay contain as adjuvants one or more cationic, anionic, amphoteric, orzwitterionic surface active agents, perfumes, antioxidants such asascorbic acid, thioglycolic acid or sodium sulfite, chelating andsequestering agents such as EDTA, thickening agents, alkalizing oracidifying agents, solvents, diluents, inerts, dispersing agents,penetrating agents, defoamers, enzymes, and other dye agents (e.g.,synthetic direct and natural dyes). These adjuvants are cosmeticadditive ingredients commonly used in compositions for coloring hair.

The hair dye compositions of the present invention are used by admixingthem with a suitable oxidant, which reacts with the hair dye precursorsto develop the hair dye. Any suitable oxidizing agent can be employed inthe hair dye product compositions of this invention, particularlyhydrogen peroxide (H₂O₂) or precursors therefor. Also suitable are ureaperoxide, the alkali metal salts of persulfate, perborate, andpercarbonate, especially the sodium salt, and melamine peroxide. Theoxidant is usually provided in an aqueous composition generally referredto as the developer composition, which normally is provided as aseparate component of the finished hair dye product and present in aseparate container. The developer composition may also contain, to theextent compatible, various ingredients needed to form the developercomposition, i.e., peroxide stabilizers, foam formers, etc., and mayincorporate one or more of the adjuvants referred to above, e.g.,surface active agents, thickeners, pH modifiers, etc. Upon mixing thehair coloring composition and the developer composition to form a hairdye product composition, the adjuvants are provided in the hair dyeproduct composition as it is applied to the hair to achieve desiredproduct attributes, e.g., pH, viscosity, rheology, etc.

The form of the hair dye product compositions according to the inventioncan be, for example, a solution, especially an aqueous oraqueous-alcoholic solution. However, the form that is preferred is athick liquid, cream, gel or an emulsion whose composition is a mixtureof the dye ingredients with the conventional cosmetic additiveingredients suitable for the particular preparation.

Suitable conventional cosmetic additive ingredients useful in the hairdye and developer compositions, and hence in the hair dye productcompositions of this invention are described below, and may be used toobtain desired characteristics of the hair dye, developer, and hair dyeproduct compositions.

Solvents: In addition to water, solvents that can be used are loweralkanols (e.g., ethanol, propanol, isopropanol, benzyl alcohol); polyols(e.g., carbitols, propylene glycol, hexylene glycol, glycerin). See WO98/27941 (section on diluents) incorporated by reference. See also U.S.Pat. No. 6,027,538 incorporated by reference. Under suitable processing,higher alcohols, such as C8 to C18 fatty alcohols, especially cetylalcohol, are suitable organic solvents, provided they are firstliquified by melting, typically at low temperature (50 to 80° C.),before incorporation of other, usually lipophilic, materials.

The organic solvents are typically present in the hair dye compositionsin an amount of from about 5 to about 30% by weight of the hair dyecomposition. Water is usually present in an amount of from about 5 toabout 90% by weight of the hair dye composition, preferably from about15 to about 75% by weight and most preferably from about 30 to about 65%by weight.

Surfactants: These materials are from the classes of anionic, cationic,amphoteric (including zwitterionic surfactants) or nonionic surfactantcompounds. (Cationic surfactants, generally included as hairconditioning materials, are considered separately below.) Suitablesurfactants, other than cationic surfactants, include fatty alcoholsulfates, ethoxylated fatty alcohol sulfates, alkylsulfonates,alkylbenzensulfonates, alkyltrimethylammonium salts, alkylbetaines,ethoxylated fatty alcohols, ethoxylated fatty acids, ethoxylatedalkylphenols, block polymers of ethylene and/or propylene glycol,glycerol esters, phosphate esters, fatty acid alkanol amides andethoxylated fatty acid esters, alkyl sulfates, ethoxylated alkylsulfates, alkyl glyceryl ether sulfonates, methyl acyl taurates, acylisethionates, alkyl ethoxy carboxylates, fatty acid mono- anddiethanolamides. Especially useful are sodium and ammonium alkylsulfates, sodium and ammonium ether sulfates having 1 to 3 ethyleneoxide groups, and nonionic surfactants sold as Tergitols, e.g., C11-C15Pareth-9, and Neodols, e.g., C12-C15 Pareth-3. They are included forvarious reasons, e.g., to assist in thickening, for forming emulsions,to help in wetting hair during application of the hair dye productcomposition, etc. Amphoteric surfactants include, for example, theasparagine derivatives as well betaines, sultaines, glycinates andpropionates having an alkyl or alkylamido group of from about 10 toabout 20 carbon atoms. Typical amphoteric surfactants suitable for usein this invention include lauryl betaine, lauroamphoglycinate,lauroamphopropionate, lauryl sultaine, myristamidopropyl betaine,myristyl betaine, stearoamphopropylsulfonate, cocamidoethyl betaine,cocamidopropyl betaine, cocoamphoglycinate, cocoamphocarboxypropionate,cocoamphocarboxyglycinate, cocobetaine, and cocoamphopropionate.Reference is made to WO 98/52523 published Nov. 26, 1998 and WO 01/62221published Aug. 30, 2001, both incorporated herein by reference thereto.

The amount of surfactants in the hair dye compositions is normally fromabout 0.1% to 30% by weight, preferably 1% to 15% by weight.

Thickeners: Suitable thickeners include such as higher fatty alcohols,starches, cellulose derivatives, petrolatum, paraffin oil, fatty acidsand anionic and nonionic polymeric thickeners based on polyacrylic andpolyurethane polymers. Examples are hydroxyethyl cellulose,hydroxymethylcellulose and other cellulose derivatives, hydrophobicallymodified anionic polymers and nonionic polymers, particularly suchpolymers having both hydrophilic and hydrophobic moieties (i.e.,amphiphilic polymers). Useful nonionic polymers include polyurethanederivatives such as PEG-150/stearyl alcohol/SDMI copolymer. Suitablepolyether urethanes are Aculyn® 44 and Aculyn® 46 polymers sold by Rohm& Haas. Other useful amphiphilic polymers are disclosed in U.S. Pat. No.6,010,541 incorporated by reference. See also WO 01/62221 mentionedabove. Examples of anionic polymers that can be used as thickeners areacrylates copolymer, acrylates/ceteth-20 methacrylates copolymer,acrylates/ceteth-20 itaconate copolymer, and acrylates/beheneth-25acrylates copolymers. In the case of the associative type of thickeners,e.g., Aculyns 22, 44 and 46, the polymer may be included in one ofeither the hair dye composition or the developer composition of the hairdye product and the surfactant material in the another. Thus, uponmixing of the hair dye and developer compositions, the requisiteviscosity is obtained. The thickeners are provided in an amount toprovide a suitably thick product as it is applied to the hair. Suchproducts generally have a viscosity of from 1000 to 100000 cps, andoften have a thixotropic rheology.pH Modifying agents: Suitable materials that are used to adjust pH ofthe hair dye compositions include alkalizers such alkali metal andammonium hydroxides and carbonates, especially sodium hydroxide andammonium carbonate, ammonia, organic amines includingmethylethanolamine, aminomethylpropanol, mono-, di-, andtriethanolamine, and acidulents such as inorganic and inorganic acids,for example phosphoric acid, acetic acid, ascorbic acid, citric acid ortartaric acid, hydrochloric acid, etc. See U.S. Pat. No. 6,027,538incorporated by reference.Conditioners: Suitable materials include silicones and siliconederivatives; hydrocarbon oils; monomeric quaternary compounds, andquaternized polymers. Monomeric quaternary compounds are typicallycationic compounds, but may also include betaines and other amphotericand zwitterionic materials that provide a conditioning effect. Suitablemonomeric quaternary compounds include behentrialkonium chloride,behentrimonium chloride, benzalkonium bromide or chloride, benzyltriethyl ammonium chloride, bis-hydroxyethyl tallowmonium chloride,C12-18 dialkyldimonium chloride, cetalkonium chloride, ceteartrimoniumbromide and chloride, cetrimonium bromide, chloride and methosulfate,cetylpyridonium chloride, cocamidoproypl ethyidimonium ethosulfate,cocamidopropyl ethosulfate, coco-ethyldimonium ethosulfate,cocotrimonium chloride and ethosulfate, dibehenyl dimonium chloride,dicetyidimonium chloride, dicocodimonium chloride, dilauryl dimoniumchloride, disoydimonium chloride, ditallowdimonium chloride,hydrogenated tallow trimonium chloride, hydroxyethyl cetyl dimoniumchloride, myristalkonium chloride, olealkonium chloride, soyethomoniumethosulfate, soytrimonium chloride, stearalkonium chloride, and manyother compounds. See WO 98/27941 incorporated by reference. Quaternizedpolymers are typically cationic polymers, but may also includeamphoteric and zwitterionic polymers. Useful polymers are exemplified bypolyquaternium-4, polyquaternium-6, polyquaternium-7, polyquaternium-8,polyquaternium-9, polyquaternium-10, polyquaternium-22,polyquaternium-32, polyquaternium-39, polyquaternium-44 andpolyquaternium-47. Silicones suitable to condition hair are dimethicone,amodimethicone, dimethicone copolyol and dimethiconol. See also WO99/34770 published Jul. 15, 1999, incorporated by reference, forsuitable silicones. Suitable hydrocarbon oils would include mineral oil.Conditioners are usually present in the hair dye composition in anamount of from about 0.01 to about 5% by weight of the hair dyecomposition.Direct Dyes: The hair dyeing compositions according to the invention canalso contain compatible direct dyes including Disperse Black 9, HCYellow 2, HC Yellow 4, HC Yellow 15, 4-nitro-o-phenylenediamine,2-amino-6-chloro-4-nitrophenol, HC Red 3, Disperse Violet 1, HC Blue 2,Disperse Blue 3, and Disperse Blue 377. These direct dyes can becontained in the hair coloring compositions of the invention in anamount of from about 0.05 to 4.0 percent by weight.Natural ingredients: For example, proteins and protein derivatives, andplant materials such as aloe, chamomile and henna extracts.

Other adjuvants include polysaccharides, alkylpolyglycosides, buffers,chelating and sequestrant agents, antioxidants, and peroxide stabilizingagents as mentioned in WO 01/62221, etc.

The adjuvants referred to above but not specifically identified that aresuitable are listed in the International Cosmetics Ingredient Dictionaryand Handbook, (Eighth Edition) published by The Cosmetics, Toiletry, andFragrance Association, incorporated by reference. In particularreference is made to Volume 2, Section 3 (Chemical Classes) and Section4 (Functions) are useful in identifying a specific adjuvant to achieve aparticular purpose or multipurpose.

The above-mentioned conventional cosmetic ingredients are used inamounts suitable for their functional purposes. For example, thesurfactants used as wetting agents, associative agents, and emulsifiersare generally present in concentrations of from about 0.1 to 30 percentby weight, the thickeners are useful in an amount of from about 0.1 to25 percent by weight, and the hair care materials are typically used inconcentrations of from about 0.01 to 5.0 percent by weight.

The hair dyeing product composition as it is applied to the hair, i.e.,after mixing the hair dye composition according to the invention and thedeveloper, can be weakly acidic, neutral or alkaline according to theircomposition. The hair dye compositions can have pH values of from about6 to 11.5, preferably from about 6.8 to about 10, and especially fromabout 8 to about 10. The pH of the developer composition is typicallyacidic, and generally the pH is from about 2.5 to about 6.5, usuallyabout 3 to 5. The pH of the hair dye and developer compositions isadjusted using a pH modifier as mentioned above.

In order to use the hair coloring composition for dyeing hair, theabove-described hair coloring compositions according to the inventionare mixed with an oxidizing agent immediately prior to use and asufficient amount of the mixture is applied to the hair, according tothe hair abundance, generally from about 60 to 200 grams. Some of theadjuvants listed above (e.g., thickeners, conditioners, etc.) can beprovided in the dye composition or the developer, or both, depending onthe nature of the ingredients, possible interactions, etc., as is wellknown in the art.

Typically, hydrogen peroxide, or its addition compounds with urea,melamine, sodium borate or sodium carbonate, can be used in the form ofa 3 to 12 percent, preferably 6 percent, aqueous solution as theoxidizing agent for developing the hair dye. Oxygen can also be used asthe oxidizing agent. If a 6 percent hydrogen peroxide solution is usedas oxidizing agent, the weight ratio of hair coloring composition anddeveloper composition is 5:1 to 1:5, but preferably 1:1. In general, thehair dyeing composition comprising primary intermediate(s) andcoupler(s), including at least one of the compounds of formula (1), isprepared and then, at the time of use, the oxidizing agents, such asH₂O₂, contained in a developer composition is admixed therewith until anessentially homogenous composition is obtained, which is applied shortlyafter preparation to the hair to be dyed and permitted to remain incontact with the hair for a dyeing effective amount of time. The mixtureof the oxidizing agent and the dye composition of the invention (i.e.,the hair dye product composition) is allowed to act on the hair forabout 2 to about 60 minutes, preferably about 15 to 45, especially about30 minutes, at about 15 to 50° C., the hair is rinsed with water, anddried. If necessary, it is washed with a shampoo and rinsed, e.g., withwater or a weakly acidic solution, such as a citric acid or tartaricacid solution. Subsequently the hair is dried. Optionally, a separateconditioning product may also be provided.

Together the hair dye composition of the present invention comprisingthe hair dye primary intermediate (1) and the developer compositioncomprising the oxidizing agent form a system for dyeing hair. Thissystem may be provided as a kit comprising in a single package separatecontainers of the hair dye composition, the developer, the optionalconditioner or other hair treatment product, and instructions for use.

Especially useful primary intermediates of formula (1) of this inventionwill provide hair coloring compositions having outstanding colorfastness, especially light fastness, fastness to washing and fastness torubbing.

DYEING EXAMPLE 1

The following composition shown in Table 1 can be used for dyeingPiedmont hair. 100 g of the dyeing composition is mixed with 100 g 20volume hydrogen peroxide. The resulting mixture is applied to the hairand permitted to remain in contact with the hair for 30 minutes. Thedyed hair is then shampooed, rinsed with water and dried. The ranges ofingredients set out in Table 1 are illustrative of useful concentrationsof the recited materials in a hair dye product.

TABLE 1 Composition for Dyeing Hair Ingredients Range (wt %) Weight (%)Cocamidopropyl betaine  0-25 17.00  Polyquaternium-22 0-7 5.00Monoethanolamine¹  0-15 2.00 Oleic Acid  2-22 0.75 Citric Acid 0-3 0.1028% Ammonium hydroxide¹  0-15 5.00 Behentrimonium chloride 1-5 0.50Sodium sulfite 0-1 0.10 EDTA 0-1 0.10 Erythorbic acid 0-1 0.40Ethoxydiglycol  1-10 3.50 C11-15 Pareth-9 (Tergitol 15-S-9) 0.5-5   1.00C12-15 Pareth-3 (Neodol 25-3) 0.25-5   0.50 Isopropanol  2-10 4.00Propylene glycol  1-12 2.00 p-phenylenediamine 0-5 1 mmole N,N-Bis(hydroxyethyl)-p-phenylene 0-5 1 mmole  diamine3-Methyl-p-aminophenol 0-5 1 mmole  p-Aminophenol 0-5 1 mmole  PrimaryIntermediate of this invention 0.5-5   4 mmoles 5-Amino-2-Methyl Phenol²0-5 3 mmoles 2,4-Diaminophenoxyethanol² 0-5 3 mmoles M-Phenylenediamine²0-5 1 mmole  Water qs to 100.00 qs to 100.00 ¹In the aggregate, theseingredients are in the range of 2 to 15% by weight. ²At least one ofthese dye precursors is typically present.

Exemplary combinations of hair coloring components employing a compoundof formula (1) of this invention are shown in Table 1 and incombinations C1 to C116 in Tables A through G. Reading down the columnsin Table A, the Xes demonstrate combinations of dyes that can beformulated according to the present invention. For example, inCombination No. C1 in Column 4 of Table A, a primary intermediatecompound of formula (1) of this invention (Row 1 of Table A) where R₁and R₂ are as defined before, can be combined with 2-amino-phenol.

Especially preferred as the primary intermediate compounds of formula(1) in such combinations of Table 1 and Tables A through G are thefollowing:

2-amino-5-phenylaminomethyl-phenol;

2-amino-5-piperidin-1-ylmethyl-phenol;

2-amino-5-pyridin-3-ylaminomethyl-phenol;

2-amino-5-imidazolin-1-ylmethyl-phenol;

2-amino-5-methylaminomethyl-phenol;

2-amino-5-dimethylaminomethyl-phenol;

2-amino-5-hydroxymethylaminomethyl-phenol;

2-amino-5-morpholino-1-ylmethyl-phenol, and

2-amino-5-dipropylaminomethyl-phenol.

TABLE A Dye Combinations Structure IUPAC Name Name C1 C2 C3 C4 C5 C6 C7C8 C9 C10 C11

X X X X X X X X X X X

2-Methyl-benzene-1,4- diamine p-Toluene-diamine

Benzene-1,4-diamine p-Phenylene-diamine

2-[(4-Amino-phenyl)- (2-hydroxy-ethyl)- amino]-ethanolN,N-Bis(2-hydroxy- ethyl)-p-phenylene- diamine

4-Amino-phenol p-Aminophenol X X

4-Amino-3-methyl- phenol 3-Methyl-p-aminophenol

2-Amino-phenol o-Aminophenol X X

Benzene-1,3-diol Resorcinol X X

2-Methyl-benzene- 1,3-diol 2-Methyl-resorcinol X

Naphthalen-1-ol 1-Naphthol X

2-Methyl-naphthalen- 1-ol 2-Methyl-1-naphthol X

2-(2,4-Diamino- phenoxy)-ethanol 2,4-Diamino- phenoxyethanol X

Benzene-1,3-diamine m-Phenylenediamine X

3-Amino-phenol m-Aminophenol X

5-Amino-2-methyl- phenol 2-Hydroxy-4- aminotoluene X

2-(4,5-Diamino- pyrazol-1-yl)-ethanol 1-Hydroxyethyl-4,5-diamino-pyrazole

TABLE B Dye Combinations Structure C12 C13 C14 C15 C16 C17 C18 C19 C20

X X X X X X X X X

X X X X X X X

X X

X

X

X

X

X

X

X

X

X

Structure C21 C22 C23 C24 C25 C26 C27 C28 C29

X X X X X X X X X

X X X X X X X

X X

X X

X X

X

X

X

X

X

TABLE C Dye Combinations Structure C30 C31 C32 C33 C34 C35 C36 C37 C38

X X X X X X X X X

X X X X

X

X X X X X X X X X

X

X

X X

X

X

X

X

Structure C39 C40 C41 C42 C43 C44 C45 C46 C47

X X X X X X X X X

X X X X

X X X X X

X

X X X X X X X X X

X

X

X

X X

X

X

X

TABLE D Dye Combinations Structure C48 C49 C50 C51 C52 C53 C54 C55 C56

X X X X X X X X X

X X X

X X X X X X

X

X X X X X X X X X

X

X

X

X

X X

X

X

Structure C57 C58 C59 C60 C61 C62 C63 C64 C65

X X X X X X X X X

X X

X X X X X X X

X

X X X X X X X X X

X

X

X

X

X

X X

X

TABLE E Dye Combinations Structure C66 C67 C68 C69 C70 C71 C72 C73 C74

X X X X X X X X X

X X X X X X X X

X

X X

X

X

X

X

X

X

X X

Structure C75 C76 C77 C78 C79 C80 C81 C82 C83

X X X X X X X X X

X X X X X X X X X

X

X

X

X

X

X

X

X

X

X X X X X X X X X

TABLE F Dye Combinations Structure C84 C85 C86 C87 C88 C89 C90 C91 C92

X X X X X X X X X

X X X X X X X X X

X

X

X

X

X

X

X

X

X

X X X X X X X X X Structure C93 C94 C95 C96 C97 C98 C99 C100 C101

X X X X X X X X X

X X X X X X X X

X

X X

X

X

X

X

X

X

X

X X X X X X X X X

TABLE G Dye Combinations Structure C102 C103 C104 C105 C106 C107 C108C109

X X X X X X X X

X X X X X X X

X

X

X

X

X

X

X

X

X X X X X X X X Structure C110 C111 C112 C113 C114 C115 C116

X X X X X X X

X

X

X

X

X

X

X

X X X X X X XWith the foregoing description of the invention, those skilled in theart will appreciate that modifications may be made to the inventionwithout departing from the spirit thereof. Therefore, it is not intendedthat the scope of the invention be limited to the specific embodimentsillustrated and described.

1. A process for the preparation of a compound of formula (1) comprising (a) reductively aininating a compound of formula (2):

with a reagent of the formula R₁R₂NH and a reducing agent to produce a compound of formula (3)

and (b) subjecting the compound of formula (3) to catalytic hydrogenation to produce a compound of formula (1)

wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₅ alkyl group, a C₁ to C₅ mono or dihydroxyalkyl group, phenyl or benzyl optionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are bound form a C₃ to C₆ saturated or unsaturated ring, optionally containing in the ring one or more additional hetero atoms selected from O, S and N atoms.
 2. A process according to claim 1 wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₃ alkyl group, phenyl or benzyl optionally substiuted with an alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are bound form a piperazine, piperidine, imidazols, imidazoline, pyridine, or morpholine ring.
 3. A process according to claim 1 wherein R₁ is hydrogen and R₂ is phenyl.
 4. A process according to claim 1 wherein R₁ and R₂ together with the nitrogen atom to which they are attached form a piperidine ring.
 5. A hair dye product comprising a hair dyeing composition containing at least one primary intermediate and at least one coupler and a developer composition containing one or more oxidizing agents, the hair dyeing composition containing a primary intermediate comprising a compound of formula (1):

wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atoms, C₁ to C₃ alkyl, C₁ to C₃ mono or dihydroxyalkyl, phenyl or beazyl optionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group, or R¹ and R₂ together with the nitrogen atom to which they are attached form a C₃ to C₆ saturated or unsaturated ring optionally containing in the ring one or more additional hetero atoms selected from O, S and N atoms.
 6. A hair dye product to claim 5 wherein the hair dyeing composition additionally comprises a primary intermediate selected from the group consisting of: 2-methyl-benzene-1,4-diamine, benzene-1,4-diamine, 2-(2,5-diamino-phenyl)-ethanol, 1-(2,5-diamino-phenyl)-ethanol, 2-[4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, 4-amino-phenol, 4-methylamino-phenol, 4-amino-3-methyl-phenol, 1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol, 2-amino-phenol, 2-amino-5-methyl-phenol, 2-amino-6-methyl-phenol, N-(4-amino-3-hydroxy-phenyl)-acetamide, pyrimidine-2,4,5,6-tetramine, 2-(4,5-diamino-1H-pyrazol-1-yl)ethanol, 1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine, and 1-(benzyl)-1H-pyrazole-4,5-diamine.
 7. A hair dye product according to claim 5 wherein the coupler present in the hair dyeing composition is selected from the group consisting of: benzene-1,3-diol, 4-chlorobenzene-1,3-diol, naphthalen-1-ol, 2-methyl-naphthalen-1-ol, 2-methyl-benzene-1,3-diol, 2-(2,4-diamino-phenoxy)-ethanol, 2-(3-amino-4-methoxy-phenylamino)-ethanol, 2-[2,4-diamino5-(2-hydroxy-ethoxy)-phenoxy]-ethanol, and 3-(2,4-diamino-phenoxy)-propan-1-ol, 3-amino-phenol, 5-amino-2-methyl-phenol, 5-(2-hydroxy-ethylamino)-2-methyl-phenol, 3-amino-2-methyl-phenol, 3,4-dihydro-2H-1,4-benzoxazin-6-ol, 4-methyl-2phenyl-2,4-dihydro-3H-pyrazol-3-one, 1H-indol-6-ol, and 2-aminopyridin-3-ol.
 8. A hair dye product according to claim 7 wherein the hair dyeing composition additionally comprises a primary intermediate selected from the group consisting of: 2-methyl-benzene-1,4-diamine, benzene-1,4-diamine, 2-(2,5-diamino-phenyl)-ethanol, 1-(2,5-diamino-phenyl)-ethanol, 2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, 4-amino-phenol, 4-methylamino-phenol, 4-amino-3-methyl-phenol, 1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol, 2-amino-phenol, 2-amino-5-methyl-phenol, 2-amino-6-methyl-phenol, N-(4-amino-3-hydroxy-phenyl)-acetamide, pyrimidine-2,4,5,6-tetramine, 2-(4,5-diamino-1H-pyrazol-1-yl)ethanol, 1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine, and 1-(benzyl)-1H-pyrazole-4,5-diamine.
 9. A hair dye product according to claim 5 wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₃ alkyl group, phenyl or beuzyl optionally substituted with an alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are bound form a piperazine, piperidine, imidazole, or morphoilne ring.
 10. In a hair dyeing system wherein at least one primary intermediate is reacted with at least one coupler in the presence of an oxidizing agent to produce an oxidative hair dye, the improvement wherein the a least one primary intermediate comprises a compound of the formula (1):

wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atoms, C₁ to C₅ alkyl, C₁ to C₅ mono or dihydroxyalkyl, phenyl or benzyl optionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are attached form a C₃ to C₆ saturated or unsaturated ring optionally containing in the ring one or mare additional hetero atoms selected from O, S and N atoms.
 11. A system for coloring hair according to claim 10 wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₃ alkyl group, phenyl or beunyl optionally substituted with an alkoxy group, or R₁ and R₂ together with the ninogen atom to which they are bound farm a piperazine, piperidine, imidazole, or morphoilne ring.
 12. A hair dyeing composition comprising, In a suitable carrier or veluicle an effectivc hair dyeing amount of: (a) at least one coupler, and (b) at least one primary intermediate comprising a compound of the formula (1):

wherein R₁ and R₁ are each individually selected from the group consisting of hydrogen atoms, C₁ to C₅ alkyl, C₁ to C₅ mono or dihydroxyalkyl, phenyl or benzyl optionally substituted with a hydroxyl, amino or C₁ to C₃ alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are attached form a C₃ to C₆ saturated or unsaturated ring optionally containing in the ring one or more additional hetero atoms selected from O, S and N atoms.
 13. A hair dyeing composition according to claim 12 comprising a primary intermediate selected from the group consisting of: 2-methyl-benzene-1,4-diamine, benzene-1,4-diamine, 2-(2,5-diamino-phenyl)-ethanol, 1-(2,5-diamino-phenyl)-ethanol, 2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, 4-amino-phenol, 4-methylamino-phenol, 4-amino-3-methyl-phenol, 1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol, 2-amino-phenol, 2-amino-5-methyl-phenol, 2-amino-6-methyl-phenol, N-(4-amino-3-hydroxy-phenyl)-acetamide, pyrimidine-2,4,5,6-tetramine, 2-(4,5-diamino-1H-pyrazol-1-yl)ethnol, 1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine, and 1-(benzyl)-1H-pyrazole-4,5-diamine.
 14. A hair dyeing composition according to claim 12 wherein the at least one coupler is selected from the group consisting of: benzene-1,3-diol, 4-chlorobenzene-1,3-diol, naphthalen-1-ol, 2-methyl-naphthalen-1-ol, 2-methyl-benzene-1,3-diol, 2-(2,4-diamino-phenoxy)-ethanol, 2-(3-amino-4-methoxy-phenylamino)-ethanol, 2-[2,4-diamino-5-(2-hydroxy-ethoxy)-phenoxy]-ethanol, and 3-(2,4-diamino-phenoxy)-propan-1-ol, 3-amino-phenol, 5-amino-2-methyl-phenol, 5-(2-hydroxy-ethylamino)-2-methyl-phenol, 3-amino-2-methyl-phenol, 3,4-dihydro-2H-1,4-benzoxazin-6-ol, 4-methyl-2-phenyl-2,4-dihydro-3H-pyrazol-3-one, 1H-indol-6-ol, and 2-aminopyridin-3-ol.
 15. A hair dyeing composition according to claim 14 additional comprising a primary intermediate selected from the group consisting of: 2-methyl-benzene-1,4-diamine, benzene-1,4-diamine, 2-(2,5-diamino-phenyl)-ethanol, 1-(2,5-diamino-phenyl)-ethanol, 2-[(4-amino-phenyl)-(2-hydroxy-ethyl)-amino]-ethanol, 4-amino-phenol, 4-methylamino-phenol, 4-amino-3-methyl-phenol, 1-(5-amino-2-hydroxy-phenyl)-ethane-1,2-diol, 2-amino-phenol, 2-amino-5-methyl-phenol, 2-amino-6-methyl-phenol, N-(4-amino-3-hydroxy-phenyl)-acetamide, pyrimidine-2,4,5,6-tetramine, 2-(4,5-diamino-1H-pyrazol-1-yl)ethanol, 1-(4-methylbenzyl)-1H-pyrazole-4,5-diamine, and 1-(benzyl)-1H-pyrazole-4,5-diamine.
 16. A hair dyeing composition of claim 12 wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₃ alkyl group, phenyl or beuzyl optionally substituted with an alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they are bound form a piperazine, piperidine, imidazole, or morpholine ring.
 17. A prcoess for dyeing hair comprising firming a hair dye product composition by mixing a developer composition and a hair dyeing composition as defined in claim 12, applying to the hair an amount of the hair dye product composition effective to dye the hair, permitting the hair dye product composition to contact the hair for period of titm effective to dye the hair, and removing the hair dye product composition from the hair.
 18. A process according to claim 17 wherein R₁ and R₂ are each individually selected from the group consisting of hydrogen atom, a C₁ to C₃ alkyl group, phenyl or benayl optionally substituted with an alkoxy group, or R₁ and R₂ together with the nitrogen atom to which they am bound form a piperazine, piperidine, imidazole, or mompholino ring. 